1. Field of the Invention
The present invention relates generally to the fields of molecular biology and medicine. More particularly, it concerns the proteomic diagnosis, classification and grading of bladder cancer based on the presence or absence of methylation in certain genes.
2. Description of Related Art
Bladder cancer is the fifth most common cancer in the United States and causes approximately 3% of all cancer-related deaths (Jemal et al., 2009). More than 90% of bladder cancers are derived from the transitional epithelium and are thus called transitional cell carcinoma (TCC). Most (75-85%) bladder cancers are non-muscle invasive tumors (pTa, Tis and pTl) at first diagnosis (Babjuk et al., 2008). Generally, the prognosis of non-invasive tumors is good, although up to 80% of cases will recur after complete transurethral resection and up to 45% of cases will progress to invasive cancer in 5 years (Babjuk et al., 2008; Kurth et al., 1995; Allard et al., 1998; Sylvester et al., 2006).
Significant costs and limitations are associated with current methods for the detection of bladder cancer. Currently, diagnosis of bladder cancer typically involves urinary cytology in combination with cystoscopy, including biopsy of suspicious lesions. Unfortunately, cystoscopy can miss 10% to 30% of malignancies and the procedure is invasive and uncomfortable (Kriegmair et al., 1996; Denzinger et al., 2007; Zaak et al., 2001). Voided urine cytology is the most common noninvasive method for detecting bladder tumors in symptomatic patients and population screening (Papanicolaou and Marshall, 1945) and has been reported to have 34-35% median sensitivity and 94-99% median specificity by meta-analyses (Lotan and Roehrborn, 2003; van Rhijn et al., 2005). Significant costs are also associated with urinary cystoscopy and urinary cytology. Clearly, there is a need for new methods for the diagnosis of bladder cancer.